When someone creates or edits a comment in JIRA, a post will be made to the Case Feed of the corresponding associated Case object and vice versa.

The post will be made if:

Chatter Feed setting is enabled in Salesforce, per the step-by-step guide below.

The JIRA or Chatter comment satisfies comment privacy and hashtag filters set by the admin.

The associated JIRA issue is not marked as 'View-only'.

Note that the Chatter post is posted by the administrator account configured for the connection. This behavior cannot be changed due to limitation of the Salesforce Chatter API. A remark, however, is provided to indicate the actual user who left the comment in JIRA.